High-grade gliomas (HGG) exert systemic immunosuppression, which is of particular importance as immunotherapeutic strategies such as therapeutic vaccines are increasingly used to treat HGGs. In a first cohort of 61 HGG patients we evaluated a panel of 30 hematological and 34 plasma biomarkers. Then, we investigated in a second cohort of 11 relapsed HGG patients receiving immunomodulation with metronomic cyclophosphamide upfront to a DC-based vaccine whether immune abnormalities persisted and whether they hampered induction of IFNγ+ T-cell responses. HGG patients from the first cohort showed increased numbers of leukocytes, neutrophils and MDSCs and in parallel reduced numbers of CD4+/CD8+ T-cells, plasmacytoid and conventional DC2s. MDSCs and T-cell alterations were more profound in WHO IV° glioma patients. Moreover, levels of MDSCs and epidermal growth factor were negatively associated with survival. Serum levels of IL-2, IL-4, IL-5 and IL-10 were altered in HGG patients, however, without any impact on clinical outcome. In the immunotherapy cohort, 6-month overall survival was 100%. Metronomic cyclophosphamide led to > 40% reduction of regulatory T cells (Treg). In parallel to Treg-depletion, MDSCs and DC subsets became indistinguishable from healthy controls, whereas T-lymphopenia persisted. Despite low T-cells, IFNγ-responses could be induced in 9/10 analyzed cases. Importantly, frequency of CD8+VLA-4+ T-cells with CNS-homing properties, but not of CD4+ VLA-4+ T-cells, increased during vaccination. Our study identifies several features of systemic immunosuppression in HGGs. Metronomic cyclophosphamide in combination with an active immunization alleviates the latter and the combined treatment allows induction of a high rate of anti-glioma immune responses.

Background. Intraoperative myelography has been reported for decompression control in multilevel lumbar disease. Cervical myelography is technically more challenging. Modern 3D fluoroscopy may provide a new opportunity supplying multiplanar images. This study was performed to determine the feasibility and image quality of intraoperative cervical myelography using a 3D fluoroscope. Methods. The series included 9 patients with multilevel cervical stenosis. After decompression, 10 mL of water-soluble contrast agent was administered via a lumbar drainage and the operating table was tilted. Thereafter, a 3D fluoroscopy scan (O-Arm) was performed and visually evaluated. Findings. The quality of multiplanar images was sufficient to supply information about the presence of residual stenosis. After instrumentation, metal artifacts lowered image quality. In 3 cases, decompression was continued because myelography depicted residual stenosis. In one case, anterior corpectomy was not completed because myelography showed sufficient decompression after 2-level discectomy. Interpretation. Intraoperative myelography using 3D rotational fluoroscopy is useful for the control of surgical decompression in multilevel spinal stenosis providing images comparable to postmyelographic CT. The long duration of contrast delivery into the cervical spine may be solved by preoperative contrast administration. The method is susceptible to metal artifacts and, therefore, should be applied before metal implants are placed.

Mobile 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. In this series, the image quality and value of intraoperative 3D fluoroscopy with intravenous contrast agent for the evaluation of aneurysm occlusion and vessel patency after clip placement was assessed in patients who underwent surgery for intracranial aneurysms.

Regulation of the host immune response serves a pivotal role in the persistence and progression of malignant glioma. To date, cytotoxic cluster of differentiation (CD)-8+ T and natural killer cells are considered the main cellular components of host tumor control. The influence of macrophages in an orthotropic C6 tumor implantation model was investigated and the aim of the present study was to characterize the effects of systemic macrophage-activation on glioma growth by using the granulocyte macrophage colony stimulating factor (rhGM-CSF). A total of 20 male Sprague-Dawley rats were orthotopically implanted with C6 glioma spheroids and treated subcutaneously with 10 µg/kg rhGM-CSF every other day; 9 animals served as controls. Serial magnetic resonance imaging was performed on days 7, 14, 21, 28, 32 and 42 post-implantation to monitor tumor volume. Histological work-up included hematoxylin and eosin, CD68/ED-1 macrophage, CD8 T-cell and Ki-67 MIB1 proliferation staining in gliomas and spleen. Experimental C6-gliomas developed in 15/20 (75%) animals. In rhGM-CSF treated rats, tumors developed significantly later and reached a smaller size (median, 134 mm3) compared with the controls (median, 262 mm3). On day 14, solid tumors presented in 11/17 (65%) rhGM-CSF-treated animals; in control animals tumor growth was detected in 3/9 animals on day 7 and in all animals on day 14. The mean survival time was 35 days in the rhGM-CSF group and significantly longer when compared with the control group (24 days). Immunohistochemistry exhibited significantly more macrophages in tumors, particularly in the perivascular zone of the rhGM-CSF group when compared with untreated animals; intratumoral CD8+ counts were equal in both groups. A systemic stimulation of macrophages by rhGM-CSF resulted in significantly reduced and delayed tumor growth in the rodent C6 glioma model. The present data suggested a significant role of macrophages in host control of experimental gliomas on the innate immune response. Until now, the role of macrophages may have been underestimated in host glioma control.

Glioblastoma multiforme is the most aggressive primary brain tumor of adults, but lacks reliable and liquid biomarkers. We evaluated circulating plasma transcripts of metastasis-associated in colon cancer-1 (MACC1), a prognostic biomarker for solid cancer entities, for prediction of clinical outcome and therapy response in glioblastomas. MACC1 transcripts were significantly higher in patients compared to controls. Low MACC1 levels clustered together with other prognostically favorable markers. It was associated with patients' prognosis in conjunction with the isocitrate dehydrogenase (IDH) mutation status: IDH1 R132H mutation and low MACC1 was most favorable (median overall survival (OS) not yet reached), IDH1 wildtype and high MACC1 was worst (median OS 8.1 months), while IDH1 wildtype and low MACC1 was intermediate (median OS 9.1 months). No patients displayed IDH1 R132H mutation and high MACC1. Patients with low MACC1 levels receiving standard therapy survived longer (median OS 22.6 months) than patients with high MACC1 levels (median OS 8.1 months). Patients not receiving the standard regimen showed the worst prognosis, independent of MACC1 levels (low: 6.8 months, high: 4.4 months). Addition of circulating MACC1 transcript levels to the existing prognostic workup may improve the accuracy of outcome prediction and help define more precise risk categories of glioblastoma patients.